where kwd is a keywordp. The effect of this event is to modify the
meaning of the :dir keyword argument of include-book and ld
as indicated by the examples above, namely by removing association of any
directory with the indicated keyword for purposes of the include-book
(and ld) :dir argument. Normally one would instead use
add-include-book-dir to associate a new directory with that keyword;
see add-include-book-dir.

Note: This is an event! It does not print the usual event summary
but nevertheless changes the ACL2 logical world and is so recorded.